(1) Field of the Invention
The present invention relates to a liquid applicator such as a felt pen (writing implement), nail art pen (cosmetic) and the like having a structure that delivers a liquid by opening and closing a valve when a writing point is pumped.
(2) Description of the Prior Art
Conventionally, there has been a well-known structure for liquid applicators, which delivers the liquid as a valve rod of a valve set is opened in linkage with pumping the writing point. When pumping is released, the valve rod of the valve set is closed.
In this case, it is necessary to choose a place for pumping, which causes inconvenience. When the applicator is pumped on the surface of paper, there is a risk of an excessive amount of liquid coming out and spoiling the surface of paper.
Further, since in this mechanism the valve rod of the valve set is moved open and closed by means of the writing point, a writing implement using a brush or other soft material as its writing tip cannot use this structure. That is, this structure is applied only to writing implements using a hard material as the writing tip such as a plastic pen core made of POM (polyacetal).
Even if a hard material is used, there has been still a problem that the tip is damaged due to excessive force on the tip during pumping so that a fine line cannot be drawn, particularly in a case of a plastic pen core.
To deal with this, there have been disclosures of technologies (Patent Documents 1 to 4 described below) in which the liquid can be delivered by a pressing operation of a click button without the need of pumping.
Japanese Patent Application Laid-open 2012-831 (:Patent Document 1) discloses a side clicking type applicator having a clicking mechanism and a valve mechanism arranged in the rear of a pen core.
Japanese Patent Application Laid-open 2006-271653 (:Patent Document 2) discloses a side clicking type fluid cosmetic container which delivers a predetermined amount of a cosmetic fluid to a brush by moving a disk inside a cartridge.
Japanese Patent Application Laid-open 2005-212418 (:Patent Document 3) discloses a side clicking type propelling mechanism which delivers a material to be applied by rotating an inner sleeve inside the front barrel to push a piston forward as a side click button is operated.
Japanese Patent Application Laid-open 2009-285255 (:Patent Document 4) discloses a side clicking type liquid propelling device in which a slide valve with a slide packing pushes a liquid from a tank portion to a liquid passage by a side clicking operation and cuts off the communication between the liquid passage and tank portion by releasing the click. This device is configured so that the click button is hidden by a cap when unused.
However, in Patent Document 1, since the click button is projected, there is a risk that the click button is clicked by mistake and the liquid is delivered wastefully, depending on the state of storage during nonusage.
Further, in Patent Documents 2 and 3, since the piston is driven as the click button is pressed, a strong force is needed to push the piston so that the liquid is hard to deliver.
Moreover, in Patent Document 4, since the click button is configured to be hidden by the cap, the cap becomes bulky so that the design is limited.